Spray type oil burner



Aug. 12, 1952 Filed March 31, 1949 R. R. WITHERELL ET AL 2,606,503

SPRAY TYPE OIL BURNER 5 Sheets-Sheet l INVENTORS.

FTTaIT/V V Aug. 12, 1952 R. R. WITHERELL ET AL 2,606,603

SPRAY TYPE OIL BURNER Filed March 51, 1949 5 Sheets-Sheet 2 Aug. 12, 1952 R. R. WITHERELL ET AL 2,606,503

SPRAY TYPE OIL BURNER Filed March 31, 1949 5 Sheets-Sheet 3 24 INVENTORS.

Fa 5 eff i IVz'Z%e ZZ.

44 any/(z g- 1952 R. R. WITH ERELL ETAL 2,606,603

SPRAY TYPE OIL BURNER Filed March 31, 1949 5 Sheets-Sheet 4 20 INV TOR i'iaierz 7?. 145 are R. R. WITHERELL ETAL 3 Aug. 12, 1952 SPRAY TYPE OIL BURNER 5 Sheets-Sheet 5 Filed March 51, 1949 Patented Aug. 12, 1952 SPRAY TYPE OIL BURNER Robert R. Witherell and Bryan Wright, Bloomington, Ill., assignors to Eureka Williams Corporation, Bloomington, 111., a corporation of Michigan Application March 31, 1949, Serial No. 84,675

- 17 Claims. 1

This invention relates to oil burners and has particular reference to certain new and useful improvements relating to oil burners of the low pressure type wherein oil and air are fed under a relatively low pressure to an oil and air mixing nozzle which discharges the mixture in the form of a fog into a secondary air stream, although the invention is not limited to so-called low pressure type oil burners.

Principal objects of the invention are to vide:

A novel and improved oil burner;

A novel and improved fuel supplying arrangement for oil burners;

A new and improved arrangement for supplying oil to the nozzle of a burner and for preventing the supplying of oil to the nozzle when the motor speed is below a desired minimum; and

A new and improved cutoff valve arrangement for oil burners.

Other and further objects of the invention will be apparent from the following description and claims and will be understood by reference to the accompanying drawings, of which there are five sheets, which, by way of illustration, show preferred embodiments and the principles thereof and what we now consider to be the best mode in which we have contemplated applying those principles. Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the purview of the appended claims. We also contemplate that of the several different features of our invention, certain ones thereof may be advantageously employed in some applications separate and apart from the remainder of the features.

In the drawings:

Fig. 1 is an elevational View, with certain parts shown in section, of an oil burner embodying the invention;

Figs. 2 and 3 are schematic views illustrating the oil and air-feeding andmixing system, Fig. 3 being a continuation of Fig. 2;

Fig. 4 is a sectional viewtaken along the line 4-4 of Fig. l;

Fig. 5 is a sectional viewtaken along the line 55 of Fig. 1;

Fig. 6 is a sectional view taken along the line 66 of Fig. 1 and showing the driving connection between the driving shaft and the metering pump and the pressure regulating valve;

Fig. 7 is a section taken along the line ll of Fig. 1;

2 Fig. 8 is a section taken along the line il8 of Fig. 1;

Fig. 9 is a section taken along the line 9-9 of Fig. 1 and showing the air pump;

Fig. 10 is a, section taken along the line Hl-Hl of Fig. 1 and showing parts of the pressure regulating valve;

Fig. 11 is a sectional view taken along the line ll-ll of Fig. 1, showing certain details of the oil metering-pump; and

Fig. 12 is a schematic view similar to Fig. 2 and showing a modified form of the invention.

.As illustrated in Figs. 1, 2 and 3, an oil burner embodying the invention comprises in general an air and liquid fuel pumping unit indicated generally at 20 which is constructed and arranged to supply oil and air to an air and oil mixing nozzle indicated generally at 22. The nozzle 22 is arranged to discharge a mixture of oil and air into a stream of secondaryair which flows through the tube or pipe 24, such secondary air being supplied by a blower wheel or fan indicated generally at 25. An electric motor 39 is mounted on the scroll or case 32 for the fan 26 and the fan 26 is mounted on the shaft 28 of the motor.

The oil and air pumping unit 20 is mounted on the fan case 32 on the side opposite the motor at, and the driving shaft 34 of the pumping unit 2c is connected by flexible coupling 36 to the end of the shaft 28 so that the operating parts of the pumping unit 20 will be driven with the fan 26.

The tube 24 projects forwardly from the lower part of the castings 38 and 40 which define the chamber 42 in which the blower wheel 26 is operatively arranged, such castings extending below the chamber and serving to conduct the air discharged by the blower wheel downwardly into the tube 24. The castings 38 and 40 form a standard or body on which are mounted the motor 39 and the pumping unit 20, as well as an ignition transformer 44 and a control indicated generally at 46. Annular openings 48 are provided between the fan case 32 and the pumping unit 20 so as to admit air to the fan air intake 50 which opens into the interior of the blower wheel 26.

The pumping unit 20 includes in general an air pump 52, a fuel supply pump 54, a metering pump 56, a pressure regulating valve 53, and a shutoff valve 60.

The air pump 52 (Figs. 2 and 9) may as illustrated be of the rotary sliding vane type and include a rotor 61 secured to the shaft 34 so as to rotate therewith, the rotor Bl being provided with a series of slots, each having a sliding vane 62 therein so that upon rotation of the rotor 6| air will be drawn through the intake 64 and discharged through the outlet 66. The intake 64 communicates with an air intake chamber 68 which is supplied with air through ports 10 and I2. A duct I4 leading from the outlet 66 conducts the air discharged by the air pump 52 to the interior of the air; pipe 16 which, delivers such air into the nozzle 22. A pressure regulating valve I8 controls a by-pass port 80 for regulating the discharge pressure of the pump 52.

Oil from a suitable reservoir is supplied to-filter chamber 82 through port 84 and through filter 86 to pipe 88 which communicates'with conduit.

60 leading to the intake 92 of the fuel supply pump 54. This pump 54 is of the gear-type and includes gear 94 mounted on shaft 34 to rotate therewith and gear 96 mounted on shaft 98, the teeth of gear 96 being in mesh with those of the gear 04 so as to pump oil through outlet I into conduit I02. Conduit I02 delivers the oil discharged by the pump 54' into bearing. chamber I04, and conduit I06 conducts oil from bearing chamber I04 into the pressure regulating valve chamber I08. is delivered into the metering. pump chamber IIO, and from the metering pump. chamber H0 oil is delivered through port II2 to the cylinders of the metering pump 56.

The metering pump 56 includes a. rotary cylin der member II4 (Fig. 11.) provided with aligned pump cylinders H 6 and M8, the cylinders Hi and IIB each having apiston I reciprocally mounted therein. The pistons each carry a cross pin I22, and a pair of springs I24 confined between the pins I2 2 biases the pistons I20 away from each other or toward their retracted position in the cylinders. The outer end I of each of the pistons bears against aring I26 which is shiftable oh center relative to the shaft 34 so as to determine the strokeof the pistons I20 aswell as to effect the delivery strokes thereof. The rotary cylinder member II4 is connected to the shaft 34 so as to rotatetherewith, as will hereinafter be described, and upon rotation of the cylinder member II-4 theouter ends I30 of the pistons will ride around the inner periphery of the ring I25. In order to effect a pumping action by the pistons I20; the ring I26 must be offset relative to the axisv of rotation of the cylinder member H4, and hence upon rotation of the cylinder member II4 the pistons I20 will move in and out in their respective cylinders.

The cylinders H6 and H8 are provided with ports I32 and I34, the port I32 registering with the port II 2 when one of the pistons I20 is in the position as shown. in Fig. 2' at. the end of its retractile stroke, while at the same time the port I34 of the other cylinder is in communication with the dischargeport I136, the piston I20 in the cylinder H8 at such time being at the end of its discharge stroke.

When the cylinder member H4 is turned 180 from the position illustrated in Figs. 2 and; 11, the piston I20 in the cylinder I I6 will have completed its discharge stroke and will have discharged oil through port I32 into port I36, while at the same time the other cylinder will be supplied with oil through port H2 and the port I34. The function of the pump 56 is to, accurately meter the quantity of oil supplied. to the nozzle of the burner.

It will be obvious that by changing the eccentricity of the ring I26 relative to the cylinder member II I, theeffective strokes of the pistons I20 may be increased or decreased, depending upon the nature of the adjustment. The position From the valve. chamber I08. oil.

of the ring I26 is determined by a leaf spring I38 confined between the ring I26 and the cylinder block I40, and a ball I42 which bears against a cam surface I 44 on an adjusting pin I45. The position of the pin I46 relative to the ball I42 is determined by a spring I48 and a screw I56, the screw I50 being threaded and secured in a threaded hole in the end plate I52 of the pumping unit so that by turning the screw I50 in its hole the pin I46 may be shifted in one direction or the other to react on the ball I42 and thereby to effect the shifting of the ring I26 transversely of the cylinder member II4, the spring I38 biasing the ring-I26 downwardly against the ball I42. Springs I4-I bias the ring' I:26 against the inner wall of the chamber I I0so as to permit adjusting movement ofthering I26.

The discharge port I34 of the metering pump 56 as shown is connected via duct I54 with the shutoff valve 60. The cylinder member H4 is provided with. a plurality: of sockets I56 which receive the ends of pins ['58 projecting from the rotor I60 of the pressure regulating valve. The face I62 of the cylinder member 4 in which the ports I34 and I32 are. provided is a smoothly fin-- ished face and seats againsta smoothly finished face I64 on the end plate I52. The end of the shaft 34' and the cylinder member II4 are provided with centering sockets in which a ball I66 is disposed so as to center and support the cylinder member II4 relative to the shaft 34.

A coil spring I68 surrounding the end of the shaft 34 reacts against the cylinder member H4 to hold the same yieldably against the surface I64 of the end plate I52. The other end of the spring I68 reacts against an inwardly directed annular shoulder on a bushing I10 which forms a part of the rotor I60 of the pressure regulating valve 58. The bushing I10 is keyed to the shaft 34 so as to rotate therewith by pin I12, and the pins I58 support the rotor I60 on the cylinder member H4. The spring I68 biases the finished face N4 of the rotor I60 against the finished face I76 provided on the left-hand end of the pressure regulating valve chamber I08.

From the foregoing it will be clear that the rotor I60 of the pressure regulating valve and the cylinder member II4 of the metering pump are driven by and with the shaft 3 and centered with respect thereto.

The pressure regulating valve chamber I08 and the chamber in which the cylinder member Il l rotates are formed byand between the end plate I52 and cylinder block I40. The pressure regulating valve comprises the rotor I60 (Figs. 6 and 10) provided with a valve chamber or radially extending passage I02 having a port I84 which communicates with the chamber I03. An inwardly facing valve seat I86 is formed around the port I84 inside of the chamber I82, and a valve in the form of a ball I88 is freely arranged in the chamber I82 and adapted under the influence of centrifugal force to move toward the seat I86 so as to close or tend to close the same and thereby to close or restrict the port I84.

The rotor I50 is bored to accommodate the bushing III) which forms a part of the rotor I60. The chamber I82 extends around the bushing I10 and on the other side thereof where it is provided with a port I90 which is in communication with an annular groove I92 in the face or end wall I16 of the chamber I 08. The annular groove I92 is in communication with a duct I94 which forms a part of a return line to the reservoir from which fuel is supplied to the port 84.

The gear pump 54 is constructed and arranged 5. to supply fuel under pressure to the meterin pump 58 through conduit I02, bearing chamber I04, conduit I00, valve chamber I08 andport II2, and the pressureregulating valve 58 is disposed in a by-pass between the dischargeside of the pump 54 and the intake side thereof, the by-pass being provided by the valve'cha'mber I 08, the port I84, the passage I82, the port I90, the groove I92 and the duct I94 which returns fuel to the fuel reservoir for the pump 54, which is the same as returning fuel to the intakeside of the pump 54. Actually, if the plug I98 were removed and the port I98 were plugged, the fuel oil Which goes through the by-pass'just described would be returned directly to the intake side of the gear pump 54 through the pipe 88 and duct 90.

When the shaft 34is not rotating, the valve member I88 will be unseatedfrom its s'eat I85 so that at such time the by-pass around thepump 54 is open. When the motor 80 begins to drive the shaft 34, the pump 54 and the rotor' I 80 will be driven and centrifugal force will urge the ball valve member I88 outwardly toward its seat I88 so as to resist the fluid flow from the discharge to the intake side of the pump 54 inwardly through the port I84, and thereby create a pressure differential.

The outward movement of the valve I88 'under the action of centrifugal force will tend to close or restrict the flow of fluid through the port I84. However, pressure will rapidly build up in the chamber I08, and as soon as the pressure in the chamber I08 exceeds the force holding the valve I 88 on its seat or urging the same toward its seat, the valve I88 will move inwardly radially and permit the by-passing of fluid back to the inlet side of the pump 54. However, as the speed of the shaft 34 increases, the centrifugal force exerted by the ball valve I88 will increase, such centrifugal force increasing as the square of the angular velocity of the shaft 34, thereby creating a pressure in the valve chamber I08 which corresponds to the square of the speed of rotation of the shaft 34.

The pressure built up in the valve chamber I08 will exist in the duct I08 and the bearing chamber I04, and this pressure is employed to open the valve 80, this pressure when applied to the valve 60 causing the same to open onlywhen a predetermined speed of rotation of "the shaft 34 has been attained and permitting the valve 80 to close when the speed of rotation of the shaft 84 drops below a predetermined speed.

The valve 80 is a shut off valve which is arranged in the fuel delivery line between the metering pump 56 and the nozzle 22, the metering pump 58 being arranged to deliver, as previously described, metered quantities of fuel oil through the port I30 and duct I54 to the valve 80, and from thence through the conduit 200 to the oil pipe 202 leading to the interior of the nozzle 22.

The valve 80 is normally closed and is opened by and in response to the pressure in the valve chamber I08, and the valve 60 is constructed and arranged so that it will not open under such pressure until the shaft ,34 attains in the neighborhood of 85-90% of its normal running speed. Thus, until the valve 80 is opened, no fuel oil will be delivered to the nozzle 22 by the metering pump 58 even though the same will be operating. The pressure developed by the metering pump 58 prior to the opening of the valve 80 may be relieved by movement of the cylinder member II4 away from the face or Wall I84 in which the ports H2 and I38 are provided. However, as soon as the shaft-34 and the rotor l00 attain sufficient speed, the movement of the valve I88 toward its seat will cause sufficient pressure to develop in the valve chamber I08 to open the valve 80, this pressure being transmitted to the valve through duct 204'.

The valve 00 comprises a seat 208 and a valve closure 208 carried by a reciprocal valve member 2I0. The valve'60 isshownopen'in Fig. 3. The valve member2l0 is slidable in a bore and is connected to a diaphragm 2I2,one side of the diaphragm being exposed to the fluid under pressure from the duct'204 while' the other side of the diaphragm is ported by means of ducts through the hollow valve member 210 and a duct 2 I 6 which isin communication with the duct I94. A spring 2I8 confined in the body of the valve 60 reacts on the diaphragm 2I2 so as to move the valve member 2| 0 and the'valve-closure 208 toward the closed position of the valve 80, and the valve 80' will close when the pressure in the duct 204 is dissipated which occurs immediately as soon as the shaft 34 and the rotor I80 fall below a predetermined speed of rotation. In other words,on deceleration'of the rotor I60 and shaft.34 from" the normalrunning speed thereof, the ball valve I88 will move to an -unobstructing position relative toits seat I'BB and the port I84 as soon as the shaft 34 'falls bel0W, say for example, -90% 'of' its normal running speed. This will dissipate the pressure in the chamber I08 and permit the'springi I8 to close the valve 80 by moving the closure 2 08 to seating position onits seat 206.

The following table'comp'utedfrom the laws governing centrifugal force illustrates the corresponding operating pressures that"can be generated at various angular speeds? In this instance, resistance to flow is created by directing the rotated mass of the ball valve I88 against the fluid stream flowing into the chamber I82 through the port I84 so as to generate hydraulic pressure in the chamber I08 as a function of the motor speed, the pressure generated being transmitted and directed against the actuating diaphragm 2I2 of the' 'shutofi'valve. Thus the shutofi valve ishyd'raulic'ally operated and is designed to be openedor closed in response to the changes in pressure developed in the chamber I08 by the pressure regulating valve 58.

Closing of the valve 80' will thus cut off the supply of oil from the metering pump 58 to the nozzle 22 as soon as the motor speed falls below 85-90% of its normal running speed. Of course the valve 80 maybeset to shut 01f the supply of oil at any predetermined pressure or any predetermined speed of the motor.

When the valve 80 is open, metered quantities of oil will be delivered through the conduit 200 to the chamber 220 in the nozzle. Orifices 222 communicating with the chamber 220 supply jets acoaeoe.

7, or oil: into passa es. 2234.; throu h. which the airlpplied; by: the. conduit HI. flows. The. m tering pump. 56 and the airpump 5 2; are, constructed and arranged: to. supply oiland; air; at: substa tially the; samelow pressure, say for example at a pressure of the orderof from to lbs, per square inch. The air; flowin throush hassages 224 will; mix; with the; oil, jets delivered through; the orifices 222 to form an emulsion which is delivered through'the nozzle opening 226 inthe, form off a... fo into the stream, of secondary air flowing in; the, direction of, the arrow through the tube 214, and, this. mixture is ignited by any suitable; ignitionmeans, such for example. as; that of the. spark, type; employing a pair of electrodes, such as; that. shown at, 228. The oil fog delivered from; the nozzle 22 will expand beyond the end. ofthe, tube 2.4-, and burn while in. suspension, the; fog, delivered by'the nozzle 22 mixing; with the secondary air to, form, a combustible mixture which will burn cleanly and efficiently, 1

The shaft; 34 is. J'purrraled in bearings 233 and 2-32; which-- form a part; or the pump unit asmbly. The pump. un t; assembly 20 is built up out of a; numberof machined parts, as shown in various; figures, which are suitably secured in assembled, relation as illustrated and provided with ducts which, conductthe oil and air through the circuits previously described. The

actual" assembly is. shownin Fig. l-, and the sec tional views, Figs. 4, 5 6,7,8, 9, and 11, correctly illustrate thev construction and shape and size of the various parts. However, in order to illustrate the-construction with particular reference to the fluid flow circuits, it; was necessary to employthe schematic Figures2 and 3. I

In order to prevent flow of, oil along the shaft, a seal indicated generally at 236 is employed, the seal comprising a running seal which prevents the flow of oil leftward along the shaft 34.

In the modification illustrated in Fig, 12 the construction is the same as that previously illustrated except in the following particulars, and to eliminate the necessity of re-describing the construction shown in Fig. 12 the same reference characters will be used as in previous figures to indicate like parts. The principal diiference between the, construction shown in Fig. 12 and that shown in the other modification resides in the specific construction of the shutoff valve although it operates in the same manner.

In this case the hydraulically operated shutoff valve includes av valve seat 3E0 shown closed by a valve member 362 in response to the actionof spring 334. The duct I54 which conducts oil dischargedby the, metering pump. 56 to the shutoff valve 358 empties into valve chamber 3:35. Fluid under pressure from the pressure regulating valve chamber I08 is supplied through duct 2% to. one side of thediaphragm 2I2 which bears against the head 2| 3 on one end of a slidable valve member 2 II, the valve member 2| I carrying the valve member 362. Thu when sufficient fluid pressure is applied to the, diaphragm 212, the valve member 362' will be unseated and oil from the metering pump 56 and the duct I54 will flow through the ducts in the hollow valve member 2 I I into the chamber 2i 5 from whence leads the conduit 200 whichsupplies oil to the nozzl 22.

The suction side, of the, pump 54 communicates through duct 216 with. the. chamber on the other side of the diaphragm 2I2 which is similar to the arrangement shown in the, previous modification. A diaphragm 21:1 separates the discharge cham- 8'. ber; 21,5 of the shutoff. valve, from the space with which, the duct 2| 6 communicates. valve member 2; has a slight clearance with respect to the bore in which it slides so that when the valve member 352 is unseated, limited quantities of oil may flow past the valve 2 I I into duct 22I which leads to the chamber 223 of the air pump 52 in which the rotor 6| operates so as to supply minute quantities of oil to the air pump 52 for reciprocating the same and also for improving the pumping efliciency thereof. Such oil as does escape into the air pump 52 will of course be delivered by the pump to the nozzle 22 through the air duct described in connection with the previous modification.

The hydraulically actuated shutoff valve shown in Fig. 12 will function in substantially the same manner as that illustrated in Figs. l-ll, and the operation of the parts shown in Fig. 12 is the same as that shown in Figs. l-ll except for the differences just described.

While we have illustrated and described preferred embodiments of our invention, it is understood that these are capable of modification and we therefore do not wish to be limited to the precise details set forth but desire to avail ourselves of such changes and alterations as fall within the purview of the following claims.

We claim:

1. An oil burner comprising a liquid fuel pump having an inlet and an outlet, a discharge chamber connected to the outlet of said pump so as to receive liquid fuel discharged by said pump, a rotor in said chamber and arranged to be driven with said pump, said rotor having a valve chamber provided with a port which communicates with said pump discharge chamber, a valve seat within said valve chamber, a centrifugally responsive valve member movable in said valve chamber upon rotation of said rotor toward said valve seat to seat thereon and close said port, a communication between the interior of said valve chamber and the inlet of said pump, a fuel metering pump having its inlet in communication with said discharge chamber so as to be supplied with fuel therefrom, said fuel meterin pump being arranged to be drivenwith said first mentioned pump and rotor, an oil and air mixing nozzle, a connection between said nozzle and the outlet of said fuel metering pump so as to supply fuel from said metering pump to Said nozzle, means for supplying air to said nozzle, a pressure operated normally closed valve in said connection, said pressure operated valve including an actuating means therefor hydraulically connected, to said discharge chamber and actuated by changes in pressure ofthe liquid in said discharge chamber above and below a predetermined value for effecting opening and closing movement of said pressure operated valve, said port, valve chamber and communication forming a by-pass between the inlet and outlet of said first mentioned pump, said valve member when seated closing said by-pass, the movement of said valve member towards said seat under the influence of centrifugal force being resisted by the fluid flow through said by-pass from the outlet to the inlet of said first-mentioned pump so as to generate pressure in said discharge chamber as a function of the rotational speed of said rotor.

2. An oil burner comprising a fluid fuel pump having an inlet and an outlet, a discharge chamber connected to the outlet of said pump so as to receive fuel discharged by said pump, a rotor 1n said chamber and arranged to be driven with The sliding;

said pump; said rotorhaving-aivalve chamber provided withia portwhich communicates with said jpump discharge. chamber, a valve seat within said valve chamber, a centrifugally responsive valve member .movable in saidivalve chamber upon rotation of said rotor toward said valve seat to seat thereon and closeisaid port, a communication between .the .in'teriorflof. said, valve chamber andtheinlet. ofsaid'pump; a fuel metering pump havingrits'inlet, in communication with said discharge chamberrso as to be supplied with fuel therefrom; said fuel metering pump being arranged toxbe driven withfsaid .first mentioned pump and'rotor, a. fuel rand air mixing nozzle constructedand arranged to mix fuel and air and to. discharge a mixture of fuel and air, a connection between said .nozzle and the outlet of said fuelmeteringpump so as to supply fuel from said metering pump tosaid nozzle, means for. supplying air to said nozzle' for mixture with they fuel' supplied thereto, axpressureoperated normally closed valve ein said connection, said pressure operated valve including anactuating means'therefor hydraulically connected to said discharge chamber .and actuated by changes in pressure of the liquid in said'discharge chamber above and below a predetermined value for effecting opening and closing movement ofsaid pressure operated valve',.said port, valve chamberland communication forming a bypass between the inlet and outlet of said first mentioned pump, said valve member when seated closing said by-pass, the movement of said valve member towards said seat under the influence of centrifugal force being. resistedbythe fluid flow through said by-pass from the outlet tothe inlet of said first-mentioned pump so as togenerate pressurein' said discharge chamber as a function of the rotational speed of said rotor, and means for flowing. a stream of secondary air past said nozzle and into which stream said mixture of fuel and air isdischarged.

3,, An oil burner comprising an' oil pump having-an inletand an outlet, and a by-pass between said inlet and outlet, a centrifugally responsive valveconstruc'ted and arranged to resist flow of oil through said'by-pass during operation of said pump thereby to create'a pressure differential between said inlet and outlet, a fuel metering device having its inletconncted to the outlet of said first mentionedp'ump so as to be supplied with oil therefrom, an oil and air mixing nozzle connected to said metering-device so as to be supplied with oil therefrom, a pressure operated normally closed valve inthe connection between said nozzle andfsaid-metering device, said pressure operated valveincluding means connected to said centrifugally responsive valve on opposite sides thereof andoperable in response to a predetermined pressure differential created by said centrifugally responsive va'lvefor opening said pressure operated valve, said pump and centrifugally responsive valve being arranged to be actuated simultaneously," means driven with saidpump for supplying air-to" said nozzlefor mixture with the oil suppliedthereto,,and means for supplying a stream of air past saidnozzle into which saidnozzle discharges a mixture of oilandair. i i 4. E011 burnerconstruction according to claim 3 wherein said centrifugally' responsive valve comprises a rotor having a valve chamber, a port communicating with'said valve chamber, a centrifugally, responsiv'ervalve 5 member arranged 'in said valve chamber and movable toward said seat under; the influence of centrifugal force, the

movement of said valve member toward said seat under the influence of centrifugal force being resisted by the fluid flow throughsaid port, said port forming part of said by-pass;

5. An oil burner comprisingan oil pump having an inlet andjjan, outlet, and a by-pas's between said inlet and outlet, a centrifugally responsive valve constructed and arranged to resist flow of oil through said by-pass during operation of said pump thereby to create a. pressure, differential between said inlet and outlet, a fuel metering device having its inlet connected to the outlet of said first mentioned pump so as to be supplied with oil therefrom, an oiland air mixing nozzle connected to said metering device so as to be supplied with oil therefrom, a pressure operated normally closed valve in the connection between said nozzle and said metering device, said pressure operated valve being responsive to and opened by a predetermined pressure differential created by said centrifugally responsive valve, said pump and centrifugally responsive valve being arranged to be actuated simultaneously, means driven with said pump for supplying air to said nozzle for mixture with the oil supplied thereto, and means for supplying a stream of air past said nozzle into which said nozzle discharges a mixture of oil and air, said pressure operated valve including an actuating diaphragm therefor, one side of said diaphragmbeing connected .to said by pass on the high pressure side of'said centrifugally responsive valve and the other side of said diaphragm being connected to said by-pass on the low pressure side of said c'entrifugally responsive valve.

6. An oil burner comprising an oil pump having an inlet and an outlet, and a by-pass between said inlet and outlet, a centrifugally responsive valve constructed and arranged to resist flow of oil through said by-pass during operation of said pump thereby to create a pressure differential between said inlet and outlet, a fuel metering pump having its inlet connected to the outlet of said first mentioned pumpso as to be supplied with oil therefrom, an oil and air mixing nozzle connected to said metering pump so as to be supplied with oil therefrom, a pressure operated normally closed valve in the connection between said nozzle and said metering pump, said pressure operated valve including actuatingmeans there for hydraulically connected to said by-pass on opposite sides of said centrifugally responsive valve and responsive to a predetermined pressure differential created-by said centrifugally responsive valve for opening said pressure operated valve, said pumps and centrifugallyresponsive valve being arranged to be actuated simultaneously, an air compressor driven with said pumps for supplying air to said nozzle'for mixture with the oil supplied thereto,means for supplying a stream of air past said "nozzle into which said nozzle discharges a mixture of oil and air, and means for supplying oil from said metering pump to said air compressor for lubricating the same. 7. An oil burner comprising an oil pump having an inlet and an outlet, a by-pass between said inlet and outlet, a centrifugallyresponsive valve constructed and arrangedto resist flow of oil through said by-pass during operation of said pump thereby to create a pressure differential between said inlet and outlet, a-fuel metering device having its inlet connected to the outlet of said first mentioned pump so as to besupplied with oil therefrom; an oiland air mixing nozzle aeoaeoe connected to said metering device so as to be supplied with oilthe'refrom, a pressure operated normally closed valve in the connection between said nozzle and said metering device, said pressure operated valve'including actuating means therefor hydraulically connected to said by-pass on opposite sides of said 'centrifugally responsive valve and responsive to a predetermined pressure differential created by said centrifugally responsive valve "for opening said pressure operated valve, means for supplying air'to said nozzle for mixture with the oil 'suppliedthereto, means for supplying a stream of air past said nozzle into which said nozzle discharges a mixture of oil and air, and an electric motor operable for actuating said pump, said 'centrifugally responsive valve andsaid air supplying means, said centrifugally responsive valvebeing constructed and arranged so that the pressure difieren'tial created thereby is not sufficient to open said pressure operated valve until said motor attains at least 80% of its normal running speed.

8. An oil burner comprisingan oil-pump having an inlet and an outlet, and'a-by-pass between said inlet and outlet, a centrifugally responsive rotary valve constructed and arranged to resist flow of oil through said by-pass'during operation of said pump thereby'to create a pressure differential between saidinlet and outlet, a fuel metering device having its inlet connected to'the outlet of said first mentioned-pump so as to be supplied with oil therefrom, an oil and air mixing nozzle connected to said metering deviceso as to be supplied with oil-therefrom, a pressure operated normally closed valve in the connection between said nozzle and said metering device, said pressure operated valve including actuating means therefor hydraulically connected to said by-pass on opposite sides of said centrifugally responsive valve and responsive to a predetermined pressure differential created by said c'en; trifug-ally responsive valve for opening :said pressure operated valve, means forsupplying air to said nozzle for mixture with the oil supplied thereto, and-an electric motor operable for driving said pump and rotating saidcentrifugally responsive valve, the resistance to flow exerted .by said centrifugally responsive valve'varying. in accordance with the square of the speed of rotation of said centrifugally responsive valve.

9. Anoil burner according to claim 1 wherein said means for'supplying air tosaid nozzle comprises an air pump arranged to be driven with said liquid fuel pump and wherein means are provided for feeding liquid fuel from said connecpumps, saidrotor and said air supplying means,

said rotor and centrifugally responsive valve member and said pressure operated valvebeing constructed and arranged so that the pressure in said discharge chamber is not sufiicient to open said pressure operated valve until said motor attains approximately 85% of its normal running speed. Y

11. An oil burner comprising a liquid fuel pump having an inlet and an outlet, a discharge chamber connected to the outlet of said pump so as to receive liquid fuel discharged by said pump, a rotor in said chamber and arrangedto be driven with said pump, said rotor having a valve chamber provided with a port which communicates with said pump discharge chamber, a valve .seat

within said valve chamber, a, centrifugally .re-

sponsive ball 'valve member :movable in'said valve chamber upon rotation'of said ro'tor'toward said valve seat to seat ithereontan'd close said .port, a communication 'between' the interior of said valve chamber and the inletof said pump; a fuel metering pump having fit inlet in communication with saidudischarge' chamber so as to be supplied with fuel therefrom: means for driving said fuel metering pump with said first mentioned pump and rotor, 'an oil 'and air mixing nozzle, acon'nection between said nozzle and the outlet of said fuelmeterin'g pump so as to supply fuel from said metering :pump to said nozzle, means for supplying air 'to said .nozzle, a normally closed "valve in said connection and an actuating 'means" therefor .hydraulically connected to said discharge 'cham'berand responsive to a predetermined liquid :pressure in said discharge chamberforopening a'id'normally closed valve, said port, valve chamber and communication forming a by-pas's between the inlet and outlet of said first =mentioned .pump, the movement of said valve member towards said seat under the influence of centrifugal force being resisted by the fluid flow through said 'by-"pass from the outlet to the inlet of said pump.

12. An oil burner comprisingan'oil pump having'an inlet and an outlet, and aby-pass between said inlet and-outlet, .e, centrifugally responsive valve including 'a centrifugally responsive 'valve member constructed and arranged to resist flow of oil through said by-pass duringoperation of said pump thereby to create a pressuredifierential between said inlet and =out1et,=- ar'fuel metering device having its inlet connected to the outlet of saidfirstmentioned pump so as 'tobe supplied with oil therefrom, an oil and air -no'zzle connected to said metering device so as to be supplied with oil therefrom,'a normally-closed'valve in theconnection between. said nozzle and said metering device, said normally closed valve including actuating means therefor hydraulically connected to-said by-pass on opposite sides of said centrifugally responsive valve and responsive toa predetermined pressure differential created by said-centrifugally responsive valvefor opening'said normally closed valve, said pump and centrifugally responsive valve-being arranged to be actuated simultaneousl-y,=means-driven'with said pump-for supplying-air 'to said nozzle, and mean for supplying -a stream of air past said nozzle into which-said nozzle discharges a mixture of oil and air. I v 7 13. An oil burner accordingto claim 1 2 wherein an 'electric motor is arranged --for driving said pump, and said Y :centrifugally responsive valve, said centrifugally responsive valve and said --normally closed valve being constructed and arranged so that said pressuredifferentialis not sufficient to cause'the opening-of said normally closed valve until said motor attains at-least-% of its 'normal'runni'ng speed.

v14. An {oil burnencomprising an oilpumphaving an inlet, an outlet, and-a-by-pass between s'aidjinlet and outlet, a centrifugally responsive valve constructed-and arranged to resist fiow of oil through said -by-:pass"during pumpoperation thereby to create a pressure differential between said inlet and outlet, an oil and airmixing nozzle connected to 'saidipump sowa's to be supplied with-oil therefrom, a pressure operated normally closed valve in the connection between said nozzle and saidpump, said pressure operated valve being hydraulically "connected to said bypass on opposite sides of said centrifugally responsive valve so as to be responsive to and opened by a predetermined pressure difierential created by said centrifugally responsive valve, said pump and centrifugally responsive valve being arranged to be actuated simultaneously, means driven with said pump for supplying air under pressure to said nozzle for mixture with the oil supplied thereto, said nozzle being constructed so as to mix the oil and air supplied thereto and to discharge a mixture of finely divided oil particles and air, means for metering the rate at which oil is supplied to said nozzle from said pump, and means for supplying a stream of secondary air past said nozzle into which said mixture of oil and air is discharged. 15. Oil burner construction according to claim 14 wherein said metering means is disposed in the connection between said pressure operated valve and said oil pump.

16. An oil burner comprising an oil pump having an inlet, an outlet, and a by-pass between said inlet and outlet, resistance means in said by-pass operative to resist the flow of oil therethrough thereby to create a pressure difierential between said inlet and outlet, a nozzle connected to said pump so as to be supplied with oil therefrom, means operative for supplying air under pressure to said nozzle for mixture with the oil supplied thereto so that said nozzle operates to discharge a spray of a mixture of finely divided oil particles and air, a pressure operated, normally closed valve in the connection between said nozzle and said pump, said pressure operated valve being hydraulically connected to said bypass on opposite sides of said resistance means so as to be responsive to and opened by a predetermined pressure differential created by said resistance means, means for metering the rate at which oil is supplied to said nozzle from said 14 pump, and means for supplying a stream of secondary air past said nozzle into which said spray of oil particles and air is discharged.

17. An oil burner comprising an oil pump having an inlet, an outlet, and a by-pass between said inlet and outlet, resistance means in said by-pass operative to resist the flow of oil therethrough thereby to create a pressure differential between said inlet and outlet, a nozzle connected to said pump so as tobe supplied with oil there- .from, means operative for supplying air under pressure to said nozzle for mixture with the oil supplied thereto so that said nozzle operates to discharge a spray of a mixture of finely divided oil particles and air, a normally closed valve in the connection between said nozzle and said pump, means hydraulically connecting said valve ;to said by-pass and operable for effecting opening of said valve when said resistance means creates a predetermined pressure differential, means for metering the rate at which oil is supplied to said nozzle from said pump, and means driven with said pump for supplying a stream of secondary air past said nozzle and into which said spray of oil particles and air is discharged.

ROBERT R. WITI-IERELL. BRYAN WRIGHT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,286,581 Scott June 16, 1942 2,378,379 Behrens June 19, 1945 2,409,504 Logan Oct. 15, 1946 2,412,383 Baker Dec. 10, 1946 2,473,347 Sanborn June 14, 1949 

